O.k. I take you work with a flash unit attached.
This has done two things:
It has created a reflection of the flashlight in the pupil of her eyes, which is good (and black and white film never displayed a 'red eye' problem).
It has only produced light for the front of her hair and that doesn't separate her from the background.
May I suspect the flash head could be turned upwards a bit and then you could attach with a elastic band a white card or aluminium foil to spread the light above her head. A sideways light or a light at her back -even from a table-top lamppost - could have helped her separate her from the background.
I know that Zenit B didn't have a lightmeter on it. Good exposure there then. The composition suits the frame as it leaves space for a cartoon-like balloon to say'Hello' or 'Hold on please, the paparazzi follow me!'
Milica herself poses too seriously and this shows she had understood what you had told her to do or decided to folow your instructions.
It's good if you make children giving their attention to you, it is as fun to be funny (but safer with digital camera as bad pictures don't cost you as much as a bad film frame)
Does she hold a phone or a toy? It is not clearly visible. A photo of her talking to a banana might had been more playful and childlike and could show some irony or contempt for the adult world
Never mind the camera you work with or play with, the result is what it matters.